Background: We present interim, blinded data exploring kinetics of viral load (VL) rebound in a randomized, placebo-controlled trial of VRC01 following analytic treatment interruption (ATI) in adults who initiated antiretroviral therapy (ART) during acute HIV infection (AHI). Study arms will be unblinded in June 2017.
Methods: Virologically-suppressed adults who initiated ART during AHI underwent ATI and randomization (3:1) to receive VRC01 40mg/kg or placebo intravenously every three weeks for up to 24 weeks. If virologically-suppressed at 24 weeks, observation continued off all therapies. Participants were monitored every 3-7 days for VL rebound and resumed ART for confirmed VL >1000 copies/ml or CD4 < 350 cells/mm3.
Results: Twenty-three Thai males were enrolled. Four received no study product and one experienced grade II generalized urticaria during the first infusion, terminating study participation without ATI. These analyses include 18 participants who initiated ART during Fiebig I (n=1), II (n=10), or III (n=7); underwent randomization and ATI; and met a study endpoint (Table and Figure). As of May 9, 2017, one participant remained off ART with an undetectable VL for 32 weeks. All other participants experienced VL rebound, restarted ART, and re-achieved virologic suppression. Ten participants had detectable VL via single copy assay (range 0.44-2.1 copies/mL) at median 10 (range 7-29) days prior to rebound >20 copies/mL. There were no serious adverse events.

Baseline Participant Characteristics (n=18)MedianRange
  Age (years)2821-50
  Duration of ART (years)3.02.3-6.6
  CD4 Count (cells/mm3)716402-1,032
Key Results (n=17; excluding one participant without VL rebound)
  Time to Rebound Viral Load >20 copies/mL (days from ATI)219-65
  First Detectable Viral Load (copies/mL)44721-7,395
  Highest Viral Load (copies/mL)3,8451,401-31,807
  Time to Viral Load <20 copies/mL (days from ART resumption)216-34
[Participant Characteristics and Key Results]

Clinical Viral Load Assessments
[Clinical Viral Load Assessments]

Conclusions: Participants who initiated ART during AHI and received VRC01 or placebo during ATI mostly experienced rapid VL rebound. Early ART alone or with VRC01 during ATI appears insufficient to delay time to VL rebound in most individuals.